Online coupons are a great way for local businesses to get new customers in the door but that popularity can quickly swamp a small business and leave customers frustrated, as one local nail bar learned after a wildly successful Groupon promotion.

Get Nailed in North Vancouver sold more than 6,000 Groupons for half-price manicure pedicures but says honouring all those online coupons has been a jugging act. The salon has been handling up to 16 Groupon customers a day for months and still has 4,000 coupons to honour by March of next year. It's now taking up to six weeks to get an appointment.

"It's not sustainable if we were to open our books to 100 per cent Grouponers. We'd be out of business in a month," said nail bar owner Adrienne Greenwood.

Greenwood says she never promised that Groupon clients would get immediate access, pointing out they're getting an extreme discount on services. But coupon holders like Julie Overnell-Carter say they should have been warned that booking an appointment could take weeks.

"I think in this case they sold a hell of a lot of Groupons, and the players, all the players didn't necessarily dot the I's and cross the T's," she said.

So what does Groupon do to make sure participating businesses, like Get Nailed, are able to handle customer demand?

"What we know from experience is that it's not a good situation for the customer or the merchant or Groupon if we oversell. So it's in everyone's best interests to be really careful about that," said Groupon Director of Communications Julie Mossler.

Despite the Groupon frenzy, Greenwood says she has no regrets. Aside from a few unhappy coupon holders, the Groupon promotion was intended to get new customers in the door.

"I think this promotion has been a huge success. It's been one of the most challenging things and one of the best things I've ever done for my business," she said.

The Get Nailed owner does have a warning for other small businesses: think long and hard before they offer a Groupon promotion they may not be able to handle. Greenwood suggests having a strategy, know what your long-term goal is and make sure you can handle the increased customer traffic.

With a report from CTV British Columbia's Lynda Steele.